Abstract

The transmitting and receiving properties of the channels of sonar arrays can change with time resulting in a degradation of the array’s performance. Fortunately, the degradation in performance can be minimized, perhaps even eliminated, if the changes in a channel’s transmitting or receiving properties are compensated for in the array’s beamformer electronics. However, this requires up‐to‐date knowledge of the acoustic performance of each of the array’s channels. This paper describes a procedure for the insitucalibration of sonar arrays when the vessel they are installed on is in open water. It can be used to determine changes in the electroacoustic performance of the projecting and receiving channels of the array. The method used is based on a procedure for insitu comparison calibration of transducers [A. L. Van Buren, ‘‘Procedure for the insitucalibration of sonar transducers,’’ J. Acoust. Soc. Am. 90, 48–52 (1991)] that uses sound‐propagation factors measured when the vessel is first deployed to account for the influence of the vessel’s structure. Results are presented that show comparisons of the measured degradation of numerous channels in a planar array using an independent acoustic measurement and the insitu method. [Work supported by ONR.]